The following are being investigated: the nature of naturally occurring and artificially produced mutant polygenes; chromosomal, isozyme, and viability variation in natural populations; relative viability as conditioned by marker chromosomes; effective population sizes; linkage disequilibria of isozyme and chromosomal polymorphisms; Loads, dominance, and genetic variances of viability polygenes; selective modes of enzymatic variants as judged by stress experiments, biochemical properties, and geographical patterns; evolutionary diversity and racial classification; distance measures based on gene frequencies and measurement attributes; analyses of gene frequencies of natural populations; loss probabilities of and numbers of heterozygotes left by neutral genes; mutation rates of isozyme genes; and mutator related phenomena. Research methods are analytical and experimental. Experimental researches are conducted mostly with Drosophila and maize.